The invention is in the field of medical devices for in situ liquid drug reconstitution in medicinal vessels.
Certain liquid drugs are preferably stored in powder form for subsequent reconstitution by a diluent which may or may not contain an active medicinal ingredient prior to administration to a patient. Single dosage vials sealed by a rubber stopper are commonly employed for storing liquid drugs in powder form. Reconstitution of the powder drug contents of such single dosage vials involves puncturing their rubber stoppers and injecting a predetermined volume of diluent. Suitable medical devices for in situ liquid drug reconstitution in single dosage vials include inter alia metal needles, plastic spikes, and a range of medical devices commercially available from Medimop Medical Projects Ltd, Ra'anana, Israel including vial adapters, MIXJECT® fluid control devices illustrated and described in Applicant's PCT International Publication No. WO 96/29113, in-line MIXJECT® fluid control devices illustrated and described in Applicant's PCT International Publication No. WO 2005/105014 (see FIGS. 1-7), and the like.
Users often have to apply a sharp initial injection force to overcome static friction at a syringe's gasket which injects a high powered stream of diluent into a vial causing its powder drug contents to foam. Users typically reconstitute a liquid drug immediately prior to use but frothy reconstituted liquid drugs take several hours to fully settle such that users have to decide to either aspirate as much of a frothy reconstituted liquid drug as possible immediately after reconstitution or reconstitute another vial in certain cases requiring precise volumes of a reconstituted liquid drug to be administered. U.S. Pat. No. 5,454,786 to Harris illustrates and describes a medical device for directing an injected flow of diluent against a vial's surface above its powder contents to avoid foaming. Similarly, U.S. Pat. No. 6,719,719 to Carmel et al. illustrates and describes a spike for directing an injected flow of diluent also above a vial's powder drug contents to avoid foaming (see FIG. 5). However, in practice, it has been found that a sharp initial injection force to overcome static friction at a syringe's gasket may inject diluent into a vial at such a rate to still cause foaming of its powder drug contents even if the injected flow of diluent does not directly impinge thereon. Moreover, a high powered stream of diluent undesirably increases the dissolving time of powder drug contents in comparison to a slow stream of diluent.